Under-floor duct system



Oct. 25, 1932. H. s. WALKER UNDER-FLOOR DUCT SYSTEM Filed-Jan. 12 1928 Patented Oct. 25, 1932 PATENT OFFICE HEBVEY S. 'WALKEB, OE ARDMORE, PENNSYLVA'H'IA UNDER-FLOOR DUCT SYSTEM Application filed January 12, 1928. Serial No. 246,108.

This invention relates to underfloor systems of electrical distribution of the type in which wiring ducts embedded in the floor structure are employed with outlets disposed at suitablepointsand leading from the ducts to the floor surface. More particularly, the invention is concerned with an underfloor system in which the ducts are provided with a multiplicity of such outlets in excess of nor- 10 mal requirements, such of the outlets as are not in use being closed by caps. A system of the type described is illustrated and de scribed in my prior Patent No. 1,592,5 i-8, issued July 13, 1926, and the present invention is directed to the provision of improvements which may be used in that system or other similar systems in which provision must be made forclosing outlets not in use.

The system of my prior patent includes ducts installed beneath the floor surface, each length of duct having a pluralityof outlets on short predetermined uniform centers so that the number of outlets will be in excess of normal demand. These outlets extend upward from the duct and terminate at the fioor surface, the outlets not in use being closed 'by caps. The caps employed preferably havea depressed central portion into 7 which floor material may be introduced so 0 that when the duct is installed with the ends of the outlets lying substantially flush with the door surface, the only visible parts of the caps are circular rims which fit over the edges of the outlets. These narrow rims are notreadily visible in the floor surface and also in some instances, the floor may not be finished evenly with the top of the outlets so that the caps are concealed by a thin film of floor material. In either case, the location 40 of the outlet cannot be readily determined by inspection and this requires that its position be located by measurement from an adjacent box, WllGIl'fl connection is to be made. 7 The cap must then be removed from the outlet and since the rim of the cap lies flush with or slightly beneath the floor surface, the removal of the cap is somewhat difficult and theusualprocedure isto chip out thefloor material-embodied in the cap and then pierce the cap by a tool to lift it clear.

In order to overcome these dilficulties, I

have devised a system in which the location of each outlet in the system is marked in the floor surface by means which are readily visible without being objectionably conspicuous, and I may also utilize these markers as a means for readily removing the caps. For this purpose, the system is provided with embedded ducts each having aplura-lity of outlets which extend to the floor surface. Each of these outlets is closed by a cap which is recessed at the top to receive floor material, and this cap is provided with a screw, the head of which normally lies flush with the top of the cap. If the top of the cap is flush with the floor, the head of the screw, together with therim of the cap, serves as a means for locating the outlet. If the floor is finished so as tocover the cap, the screw may be backed out a few turns so as to bring its head flush with the floor surface to serve as a marker. The screw also serves as a convenient means for removing the cap and by unscrewing the screw to bring its head slightly above the floor, the head serves as a means which can begripped by a suitable tool to lift the cap free.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which Fig. 1 is a plan View of a portion of a duct system;

Fig. 2 is a vertical sectional view through one of the outlets, and

Fig. 3 is a vertical sectional view through the closurecap, with the parts in a position facilitating ready removal.

The system as illustrated is of the three duct type, each duct 10 being of any suitable material, such as steel tubing of square section. The runs of ductfare placed in the desired direction on the floor and at intersections, boxes 11 of suitable construction may be used. The ducts are preferably supported on the rough floor slab in mountings, and in the completion of the floor structure, filling material is placed over and around the ducts and the floor finished by the usual layer of cement mortar. Each duct is provided with tubular outlets 12 and these outlets may be preset, that is mounted in the duct prior to its installation, or else later installed by cutting through the floor and into the duct. These outlets are of metal and mounted in openings in the duct wall in any convenient manner, such as that illustrated at 13. These outlets extend through the floor material and preferably terminate substantially flush with the finished floor surface, although in some installations the level of the floor material is above the top of the outlet. As many more outlets are provided than are required in normal use, the outlets not used are closed by caps 14 which are mounted removably in the ends of the outlets. I

The cap used for the purpose is of metal and it has a central depressed portion 15 which has an outer diameter substantially the same as the inner diameter of the outlet, thus insuring tight frictional engagement. The cap also has a projecting peripheral rim 16 which fits over the upper end of the outlet to make a water-tight closure. At the center of the depressed portion, a boss 17 is mounted in the cap as by having a portion 18 inserted in an opening in the cap and spun over to grip the cap tightly. This boss has a threaded bore extending through it, and in this bore is a screw 19. The top of the boss is countersunk as at 20, and the top lies substantially in the plane of the rim so that when the screw is turned in as far'as possible, the head 21 lies flush with the to of the cap or with the floor level and its oter end 22 projects into the interior of the outlet a substantial distance.

When the caps are in place in a completed installat on, the space in the top of each cap around the boss will be filled with floor material so that only the rim and the head of the screw are Visible. Preferably the screw is made of brass to prevent rusting and to make it more easily detected in the floor, and the cap is thus readily found and the location of the outlet discovered. When an outlet is to be opened for a connection, the screw is turned out of the cap a sufficient distance to permit its head tobe gripped by a. suitable tool and the cap can thus be readily removed and in such condition that it may be used again.

The boss 17 serves another useful purpose in that it acts as an anchoring means for the plug of cement with which the depressed portion of the cap is filled when the floor is completed. This plug is made by introducing wet cement mortar into the top of the cap and when the cement sets, there is a likelihood that the mass will shrink and pull clear of the walls so that the plug might work loose.

With the boss 17 in place in the cap, this difliculty is obviated because the sides of the boss are undercut as illustrated and an interlock between the plug and the cap is secured, thus effectively anchoring the plug in 55 place.

The improved system of this invention accordingly includes a plurality of outlets each of which, when not in use, is provided with a marker that can be found in the floor surface without difliculty, so that determining the locations of inserts by measuring from the boxes is avoided. Also, each of these markers serves the additional purpose of affording means for easy removal of the caps and the added cost for this type of cap is so small as to be unimportant. Wh le the improved cap is particularly useful in a system constructed in accordance with the disclosure of my patent, in every underfloor system, outlets are likel to be installed and their use temporarily discontinued, and the cap is useful in that connection also. I

I claim:

1. In an underfloor wiring system, the combination of a wiring duct disposed within the floor structure at a distance beneath the finished floor surface, an outlet communicating with the interior of the duct and providing'means for leading wirin therefrom,

a closure for the end of said out et having a portion substantially flush with the floorsurface and carrying a quantity of floor material forming the greater part of the exposed surface of said closure, and marking and removing means carried by said closure and visble at the floor surface.

2. In an underfloor wiring. system, the combination of a wiring duct disposed within the floor structure at a distance beneath the finished floor surface, an outlet communicating with the interior of the duct and providing a passage for leading wiring therefrom and a closure for the end of said outlet provided with a marking device visible in the floor surface, said device also affording means for removing said closure, said closure having a portion substantially flush with the floor surface, and a depressed portion carrying floor material forming substantially the entire remaining surface of said closure.

p 3. In an underfloor wiring system, the com bination of a wiring duct, an outlet leading from the duct, and a closure for the outlet, having a recess for receiving a quantity of floor material and means for removing said closure, said closure lying substantially flush with the floor surface whereby said quantity of floor material received therein forms the greater part of the exposed surface of said closure with said removing means visible at the floor surface. I

4. In an underfloor wiring system, the combination of a wiring duct, an outlet leading from the duct and a closu refor the outlet provided with a marker which also afl'ords means for removing the closure from the outlet, the major portion of the surface of the closure being formed by floor materialcarried thereby, and saidmarker lying flush with the floor surface and visible therein.

5. In an underfloor wiring system, the combination of a wiring duct, a tubular outlet in the duct wall, a cap received in the end of the outlet for closing it, said cap carrying floor material forming substantially the entire exposed surface of the cap and means attached to the cap by which it may be readily removed, said removal means being flush with and visible in the floor surface.

6. In an underfloor wiring system, the combination of a wiring duct, an outlet in communication with the interior of the duct, and a cap for closing-the outlet having a cavity for receiving a substantial quantity of floor material and means for removing said cap including a screw disposed centrally'of the cap and normally lying with its top flush with the floor surface.

7 In an underfloor wiring system, the combination of a wiring duct, an outlet in communication with the interior of the duct, a cap mounted in the outlet and having a ortion overlying the end of the outlet, the middle of the cap being depressed into the outlet to receive a plug of floor material, and combined marking and removing means carried by said cap embedded in said plug of floor material, said means including a boss disposed centrally of said cap and a screw threaded into said boss and normally lying with its upper end flush with the floor surface.

8. In an underfloor wiring system, the combination of a wiring duct, an outlet in communication with the interior of the duct, a cap mounted frictionally in the outlet and having a plug of floor material forming substantially the entire exposed surface of the cap, and a combined marking and removing device carried by the cap and having a portion terminating and visible in the floor surface, this device also assisting to hold the plug in position.

9. In an underfloor system, the combination of a wiring duct mounted in a floor below the level of the surface, an outlet in communication with the interior of the duct and extending toward the floor surface, a closure for the outlet mounted therein and carrying a quantity of floor material which covers substantially the entire surface of the closure, 7

and combined marking and removing means carried by said closure embedded in said floor material carried thereby and including a marker disposed centrally of the closure and terminatin substantially flush with and visible in the oor.

10. In an underfloor system, the combination of a wiring duct mounted in a floor below the level of the surface, a fitting in communication with the interior of the duct and extending toward the floor surface, a closure for the fitting mounted therein and carrying a quantity of floor material which covers substantially the .entire surface of the closure,

and means carried by the closure for facilitating the removal thereof and lying within the said floor material carried by the closure, said means including a part terminating substantially flush with and visible in the floor.

11. In an underfloor system, the combination of a wiring duct mounted in a floor below the level of the surface, an outlet in communication with the interior of the duct and extending toward the floor surface, a closure for the outlet mounted therein and partially overlain by floor material, and combined marking and removal means carried by said closure and embedded in the floor material overlying said closure, said means including a marker disposed centrally of said closure and adjustable therein, said marker normally lying with its upper end substantially flush with and visible in the floor.

12. In an underfloor wiring system, the combination of a. wiring duct, an outlet communicating through a wall of the duct with the interior thereof and affording access thereto, a cap removably mounted in the free end of the outlet and having a depressed central portion, the depression in the cap normally containing a substantial quantity of floor material, and means carried by the cap for marking and removing the latter includ-- ing a screw disposed centrally of the cap and normally lying with its head flush with the floor surface.

13. In an underfloor wiring system for use in concrete floors, the combination of a wiring duct disposed in the floor a substantial distance below the floor surface, an outlet communicating through a wall of the duct with the interior thereof and affording access thereto, this outlet projecting upwardly from the top of the duct toward the floor surface, 3

a cap removably mounted in the upper end of the outlet and normally lying with its top accessible in the floor surface, the cap having a central depression normally containing a substantial quantity of floor material concealing the major portion of the cap, and means carried by the cap for marking and removal of the latter including a boss on the central portion of the cap lying within the floor material, and a screw threaded into said boss, said screw normally lying with its upper end flush with and visible in the floor surface.

In testimony whereof I alfix my signature.

HERVEY S. WALKER. 

